Electrical instrument



Aug. 29, 1950 'r. J; SMULSKI ELECTRICAL ms'mumsn'r Filed April 22, 1946 BJMETAL.

INVENTOR.

Theodore J- Smulski BY Patented Aug. 29, 1950 ELECTRICAL ms amm Theodore J. smuau, Ga ma; anignor to Productive Inventions, s Ina, a corporation Application April as, 1020. Serial No. 663,812

My invention relates to electrical instruments and more particularlyto electrical indicating instruments having a heated'bimetallic actuating member. I

This application is a continuation in part of my abandoned application, Serial No. 454,674, filed August 13, 1942.

My invention is particularly adapted for use in a remote indicating system having a sending instrument provided with bimetallic means which control the transmission of power in accordance with a variable factor to be indicated. and a bimetallic actuated indicating instrument energized by the power so transmitted. Heretofore the instruments used in such systems have been.

compensated for ambient temperatures so that the accuracy thereof has been satisfactory where there was no great difference between the ambient temperature at the sending or transmitting instrument and the ambient temperature at the receiving or indicating instrument. when such indicating systems and instruments are used under certain conditions where the ambient temperatures at the transmitting and receiving stations are different, certain factors are encountered for which correction or compensation must be made. For example, if a remote indicatin system of the type mentioned is used on aircraft the ambient temperature at the transmitter may be low due to the high altitude, and the temperature at the receiving instrument may-ibe relatively high due to the fact that the receiving instrument is mounted in a heated cabing;

When the sending and receiving instruments have bimetallic elements of like construction, have like heating elements therefor. and convert a icolilim'. (01. 111-95) rections are accomplished by providing some means whereby at the higher ambient temperatures the bimetallic actuating member of the receiving instrument may provide an indication by multiplying the effective deflection of the actuating member by a compensating factor or by decreasing the eiIort required to produce the indication.

In a remote temperature indicator of the wattage integrator type, the electrical energy converted to heat at the receiver is a function of the temperature of the sender environment. The ambient temperature of the receiver will aflect the influence of a given sender temperature upon the receiver unless compensation is provided, be-

cause a larger proportion of the electrical energy converted to heat at the receiver will be lost. through radiation at high ambient temperature .of the receiver than at low ambient temperature ally multiplied by a factor which changes with electricityto heat at equal rates, the dissipation I erable diflference in the ambient temperatures between the two instruments so that the ambient temperature at the receiving instrument is higher, the loss of heat at the receiving instrument is at a rate much greater than the loss of heat at the transmitting instrument. This change in the rate of heat loss must be taken into consideration in order to provide accurate indication.

In certain instances it has been proposed to utilize an indicating instrument having bimetallic actuating means to indicate the electrical condition of the electrical system of a craft and in such case the heat loss must be taken into consideration in order to provide accurate indication. In accordance with my invention these corthe ambient temperature thereby to provide accurate indication.

Other and further objects otflmy invention will become more readily apparent by reference to the following specification taken in connection with the accompanying drawing wherein:

Figure 1 is a top view of the ntial elements of an indicating instrument constructed in accordance withthe present invention;

Figure 2 is a perspective view of certain of the 4 elements of the indicating instrument so as to the indicating instruments may be modified in accordance with the present invention.

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Referring more particularly to Figures 1 and 2 of the drawing, there is shown a cup-shaped housing and bas member H within which are supported certain operating elements of the indicating instrument. A suitable dial may be supported by the rim or flange of the cup-shaped housing so that an indicating hand projecting through a suitable opening in the'dial will' provide the desired indication. "The base of the housing II has pivotally mounted thereon an arm I 2 provided with a perforation through which a headed pin or'rivet l3 extends so that the arm 12 is pivotally mounted and frictionally secured in position on the base II. The arm I2 is provided with a gear sector portion 14 located at a distance from the pivot stud l3 and positioned adjacent an aperture 45 in the base II. By inserting a geared tool from the bottom of theuhousing ll into the opening IS the gear sec'tor portion l4 of the arm i2 may be engaged so that .by rotation of the tool, the arm l2 may be moved to a predetermined position at the time when the instrument is being initially adjusted. Adjacent the outermost end of the arm l2, there is an upstanding portion 5 to which there is secured a bimetallic member l7, best seen in the perspective showing in Figure 2. The

bimetallic member I! is formed so as to be of a generally U-shaped configuration having an ambient temperature compensating leg heated leg I9 and an interconnecting portion 2|. The heated leg I9 is provided with an electrical heating elerfient 22 which is connected between a pair of conductor studs 23 and 24, each of which is secured in the base II by suitable insulating washers 25 and 25. In order to determine what portionof the ambient temperature compensating leg I8 is to be effective for this compensation, a portion of this leg may be turned at right angles thereto as at 21 thus rendering'that portion of the leg ineffective. In

order to prevent the interconnecting portion 2| from having any movement or action it has been 'found preferable to provide a curved corrugated configuration for the interconnecting portion. Adjacent the end of the bimetallic leg I 9 there is a transverse bimetallic portion 23 which terminates in a hook portion 29. The transverse portion 28 introduces a compensating factor for correcting for the increase in the heat loss which occurs for a given rate of electrical heating with rise of ambient temperature.

The indicating instrument is provided with an indicatingahand or member 3|, the pointer por- I tion of which extends above the dial which is I secured to the flange or rim of the cup-shaped housing, the pointer having two right angled bends therein adjacent the narrow strip 32 to permit the pointer portion to extend above the dial. The indicating member 3| extends a short distance underneath the dial and it is provided adjacent the end thereof with a right angle portion 33 having therein an aperture 34. The indicating member 3| is pivotally mounted by means of the aperture 34 in the right angle portion 33 by having one side of the aperture 34 engaging the hook 29 0f the bimetallic actuating member l9 and having the other side of the ed arm 39. The pivotally mounted arm 39 is provided with an aperture through which there extends a pivot'stud or fastening means 4! which pivotally and frictionally secures the arm 39 to the .bottom of the housing H. Adjacent the outer end of the arm. 39 there is provided a gear sector 42 positioned adjacent an aperture 43 in the base of the housing I I so that by means of a geared tool the arm 39 may be moved to a particular position during the initial adjustment of the instrument.

Referring to Figure 3 there is shown an electrical circuit in which an instrument of the type shown and described in connection with Figures 1 and 2 may be used. This circuit includes, as diagrammatically shown in Figure 3, an indicating instrument having a spring support member 31, an indicating hand 3|, a bimetallic actuating member I? and a heating element 22 therefor, these parts desirably being constructed as shown in Figures 1 and 2. Where the instrument is to be used to show the condition of an electrical circuit, the heating element 22 is connected at one terminal thereof to a suitable source of electric potential 44 which in turn is connected to ground. The other terminal of the electrical heating unit is connected to a terminal A which in turn is connected to the other side of the electrical system or to ground. If the terminal A is connected to ground or to the other side of the circuit, the indicating instrument operates to show the voltage condition of the power source 44. Since the ambient temperature compensated actuating member l9 will be heated to different values depending upon the voltage of source 44 and the ambient temperature of the instrument may vary over a relatively wide range, there must be provided some means for compensating for thi difierence in the rat of heat loss. This is accomplished by using the bimetallic portion 28 in the arrangement shown in Figure 1 or by any of the other arangements subsequently to be described.

Where the electrical instrument is to be used to indicate a, variable factor, as in a liquid level gauge, the terminal A is connected to a terminal B which, in turn is connected to an electrical heating element 45 which surrounds a bimetallic leg of a transmitter unit 46. The transmitter unit 46 is desirably of the same construction as the receiver unit, comprising a V-shaped bimetallic element having the parts i8, I9, 2| and 28, the spring 31, and a loop 33 connecting 28 and 31. Adjacent the free end of the bimetallic element there is an electrical contact 4! which cooperates with a, mechanically movable electric contact 48 which in turn is connected to ground. If for example, the variable factor to be indicated is the level of a liquid, there will be proaperture 34 engaging the hook portion 36 of a spring sup orting member 31. The indicating hand 3| therefore is pivotally supported by two knife edge supports.

v, The spring support member 31 is connected by a suitable rivet or suitable fastening means to an upstanding portion 38 of a pivotally mountvided a suitable float 49 connected to actuate a cam 5! which operates against a cam follower 52 so as to move the contact 48 to a position corresponding to the level of the liquid. Transmitting instruments of the type suitable for use in the circuit of this type may be any of the instruments shown in United States Letters Patent No. 2,006,608, granted July 2, 1935 upon the application of T. J. Smulski; Reissue No. 21,527, granted August 6, 1940 upon the application of T. J. Smulski; or Patent No. 2,133,077, granted October 11, 1938 upon the application of Leonard Boddy. Such transmitting instruments are utilized in an electrical indicating system in which a variable factor is indicated at a remote point from the transmitting unit by the transmission 8 of a series of current pulsations. Such systems are known in the art and are illustrated by United States Letters Patent No. 1,888,048, granted October 25, 1932 upon the application of F. M. Slough.

The operation of the electrical circuit shown in Figure 3 may be briefly described by stating that it will be assumed that the liquid level causes the adjustable contact 48 to be moved to a particular position. Electrical energy flowing through the circuit from the source 44 produces heating of the transmitter leg of the ambient temperature compensated bimetallic element 48 by means of the electrical heating element 48 thereof so that the bimetallic element is warped thus tending to move the electrical contact 41 away from the contact 48 thereby to breakthe circuit. If the circuit is broken the bimetallic element 48 begins to cool so that contact is againestablished between the contacts 41 and 48 and by repetition of this action additional current impulses are caused to be transmitted to the indicating unit. This making and breaking of the contacts occurs at a relatively rapid rate and the impulses of power thus transmitted serve to provide heating of the receiver leg I8 oi the bimetallic actuating member I! by means of the heating element 22 so that the bimetallic element II will cause the indicator 3| to assume a position such that it indicates the condition of the sender and receiver are the same, the heat.

asi es? ing spring 8'! thereby in effect reducing the amount of bias against which the actuating leg I8 will operate. This reduction of the bias exerted by the spring 81 at high ambient temperatures permits the mechanical force of the heated bimetallic leg I8 to produce a slightly greater movement of the indicating hand 8| thereby to produce substantially the same extent of movement of the pointer for a given change of the factor to be indicated, regardless of the ambient temperature of the receiver.

While, in the arrangements shown in Figures 1 and 2. the mechanical bias of the spring member 81 has been reduced by a bimetallic portion 28 located adjacent the free end of thebimetallic member I8, it is possible to produce a similar reduction of the mechanical bias by other arlosses are the same and accurate indication will be obtained. If the ambient temperature at the receiver is higher than that at the transmitter and the amounts of electrical energy converted to heat at the receiver and the transmitter are rangements. I

Thus, for example. in Figure 4 there is again shown an indicating instrument having a housing Ila provided with a pivoted arm I2a secured by a stud Ila so that the arm I2a may be adiusted by means of a gear sector I4a. positioned adjacent an aperture I8a in the bottom of the enclosure Ila. The supporting enclosure Ila is also provided with another arm 38a which is provided with a gear sector 42a positioned ad- Jacent an aperture 48a in the bottom of the supporting frame. The arm 38a is provided with an upstanding portion 88a which in turn supports the spring support member 81a. The arm In is provided with an upstanding portion I84 which in the present instance is at substantially right angles to the portion I8 of the corresponding arm I2 in Figure 1. Mounted on the portion l8a oi Figure 4 there is a bimetallic actuating member which has a bimetallic portion 83, an ambient temperature compensated leg 84, a connecting portion 88 and an actuating leg 88 which is provided with a suitable heating element. The end of the actuating leg 88 is provided directly with a hook portion which in turn engages a suitable indicating pointer in a manner similar to that shown in Figure 2. In the the same, there will be a greater heat loss at the receiver, thus producing inaccurate indication. I

At the higher ambient temperature the rate of heat loss will be considerably greater than at:the 1 lower temperature and hence the heating eflect.

produced by the current flowing through the heating element 22 will not produce as great movement of the indicating pointer for a given change of the condition to be indicated as would be the case at a lower ambient temperature the receiver. Since the indicating pointer 8I i's supported by a knife edge mounting which includes a mounting spring 31, any action of the leg I8 is one which is opposed to a certain degree by the bias exerted by the spring mounting 31. At the time that the instrument is initially calibrated the bias exerted by the mounting member 31 is controlled by adjustment of the position of the leg or arm-39 as determined by the operator by means of a gear tool inserted in the aperture 43 which engages the gear sector 42. In the arrangement shown in Figure 1, the bimetallic member 28 is positioned in a generally transverse direction to the direction of the bimetallic leg I9, so that the high ambient temperatures will cause this portion 28 to move at substantially right angles to the movement of the leg I! and in a direction toward the mountpresent arrangement the ambient temperature increase produces a warping of the bimetallic portion 88 so as to reduce the amount of mechanical bias exerted upon the actuating leg 88 and at the same time there is introduced by virtue of its position by the bimetallic member 83, a correction factor which changes the eflective pivot of the actuating hand of the indicating hand 3|. This occurs because the bimetallic portion 88 is positioned at the end of the ambient temperature compensating leg 84. Thus this bimetallic portion 83 produces in effect a sort of rotation of the entire bimetallic actuating assembly comprising the ambient temperature compensating leg 84 and the interconnecting portion 85 into actuating member 88. It is believed that from this description no further explanation of the operation is necessary as this will be readily understood by those skilled in the art.

Instead of having a bimetallic portion such as 88 in Figure 4 which simultaneously reduces the mechanical bias and shifts the pivot oi the indicating hand, there may be provided a separate bimetallic element as is shown in Figure 5. Thus in Figure 5 there is provided a housing IIb having therein a pivoted member |2b provided with an upstanding portion I8b which in turn supports a bimetallic member 81 to the outer end 01' which there is connected by suitable means a bimetallic actuating assembly comprising the compensating leg II, the inter- I connecting portion is and the heated leg II. A

second pivoted member 39b is provided with an portion of the spring supporting member flb.

By virtue of the fact that the bimetallic member I! is positioned on the other side of the bimetallic actuating assembly, the assembly will move in a direction opposite to the movement of portion s: of Figure 4, the bimetallic member 51 tending to move toward the center of the housing llb with increase of ambient temperature. This produces a rotation of the bimetallic members 58, so, and 6|, thus changing the effective pivot of the indicating hand and also changing the mechanical bias which is exerted by the spring member 3112.

If desired, compensation for changes of hea losses with change of ambient temperature may be introduced by such arrangements as are shown in Figures 6 and 7. For example, in Figure 6 there is shown an arm 390 which is provided with an upstanding portion 380 which in turn supports a spring member 31c having secured to the outer end thereof a bimetallic member 62 which has at its free end a hook portion 63 for engagement with the apertured portion of the indicating hand. In such arrangement the bimetallic member 62 at increased ambient temperatures will warp toward the center of the instrument thereby reducing the mechanical bias against which the bimetallic actuating member must operate without any substantial change in the effective pivot of the indicating hand. Another way of accomplishing substantially the same result as was done by the arrangement shown in Figure 6 may be by the means shown in Figure 7. Figure 7 therefore shows an arm 39d provided with an upstanding portion 38d which in turn supports a spring support member 31d. Mounted adjacent to a portion of the spring member 31d is a bimetallic portion 64 which is so positioned that at the high ambient temperatures the bimetallic portions 64 will warp toward the center of the instrument housing thereby to relieve or reduce the mechanical bias which may be exerted by the spring arm 3111 upon the indicating hand without any effective change in the pivot thereof.

While for the purposes of explanation of my invention there have been shown certain specific embodiments, it is to be understood that I am not to beJimited thereto since obviously modifications may be made in the instrumentalities employed without departing from the spirit and scope of my invention as set forth in the appended claims.

I claim:

1. An electrical instrument having a bimetallic member for actuating an indicator, said member having a first portion thereof provided with an electric heating element adapted to be energized in accordance with the condition to be indicated, a'second portion operatively con nected to said first portion for efiecting compensation for distortion of the first portion caused by variations of ambient temperature, and a third portion operatively connected to said first portion to supplement the action to be produced by said heated portion, and a pointer actuated by said member, said third portion being operatively connected to said pointer and arranged to increase in response to ambient temperature rise, the extent of move-- ment of the pointer produced by said first portion in response to a given rise of temperature of the first portion above the ambient temperature thereby to compensate for the increase in heat loss of said heated portion at higher ambient temperatures. I

2. An electrical instrument having means for actuating an indicator, said means including a bimetallic portion provided with an elec;

tric heating element adapted to be energized in accordance with the condition to be indicated, a second bimetallic portion operatively connected to the first portion for effecting compensation against any change which may occur in the first portion caused by variations of ambient temperature, and a third bimetallic portion operatively related to the first and second portions to supplement the action to be produced by said first ortion, and said third portion being arranged to increase in response to ambient temperature rise, the extent of movement of the indicator produced by said first portion in response to a given rise of temperature of the first portion above the ambient temperature thereby to compensate for the increase in heat loss of said heated portion at higher ambient temperatures.

3. An electrical indicating instrument com-, prising, in combination, a bimetallic actuating member which includes an actuating leg and an ambient temperature compensating leg, electrical heating means for the actuating leg, an indicating member actuated by said bimetallic actuating leg, means cooperable with the actuating leg for applying a mechanical bias to oppose the movement of said actuating leg, and a further bimetallic means unitary with the actuating, member actable on the indicating member and responsive to ambient temperature to reduce said bias as the ambient temperature increases.

4.1m electrical indicating instrument comprising, in combination, bimetallic means which includes a bimetallic actuating portion and an ambient temperature compensating portion, electrical heating means for the actuating portion, an indicating member actuated by said bimetallic actuating portion, means co'operablefwith the bimetallic means for applying a mechanical bias to control the movement of said indicating meniber, and a bimetalllcportion operatively associated with said bimetallic means responsive to ambient temperatureto vary said bias as the ambient temperature increases.

5. An electrical indicating instrument com: prising, in combination, a bimetallic actuating member, electrical heating means therefor, means for mechanically opposing movementbt a portion of said member, and bimetallic means unitary with said member both for com-Be ea h,

ing distortion of said member caused by variation of ambient temperature, and for reducing the mechanical opposition to movement inre'- change which may occur in said member caused by variation of ambient temperature, and for varying the mechanical opposition to movement in response to rise of ambient temperature,

an actable portion directly connected to the attaching part of the indicator, and a member directly connected to said attaching part, said actable portion and said member being constructed and arranged whereby one may be influenced to increase in response to ambient temperature rise, the extent oi! movement of the indicator produced by said first portion in response to a given rise of temperature of the first portion above the ambient temperature thereby to compensate for the increase in heat loss of said heated portion at higher ambient temperatures.

8. An electrical instrument comprising means for assisting in the actuation of an indicator provided with an attaching part, a first portion 01' bimetallic material provided with an electric heating element adapted to be energized in accordance with the condition to be indicated, a second portion of bimetallic material for eflect-' ing compensation for movement of the first portion caused by 'variations oi. ambient tempera-' ture, said first portion including an actable por tion connected toth'e attaching part of the indicator, and a member connected to said attaching part, said actable portion and said member being constructed and arranged whereby one may be influenced to increase in response to ambient temperature rise, the extent 01. movement oi. the indicator produced by said first portion in response to a given rise of temperature of the first portion above the ambient temperature thereby to compensate for the increase in heat loss of said heated portion at higher ambient temperatures, said last-mentioned portions providing the means for supporting said indicator in portion of bimetallic material provided with any electric heating element adapted to be energized in accordance with the condition to be indicated, said first portion also being provided with continuation means for directly connecting said first portion to said attaching part, a second portion of bimetallic material operatively connected to the first portion for effecting compensation for any change in the first portion caused by variations of ambient temperature, and means directly connected to the attaching part of the indicator, one of said means being of a character to increase in response to ambient temperature rise, the extent of movement of the indicator produced by said first portion in response to a given rise of temperature of the first portion above the ambient temperature thereby to compensate for the increase in heat loss oi! said heated portion at higher ambient temperatures.

temperature compensating portion,

means for assisting in the actuation of an indicator provided with an opening, said means including a first portion provided with an electric heating element adapted to be energized in accordance with the condition to be indicated, a connection means provided on said first portion disposed in said opening assisting to connect said first portion to said indicator, a second portion operatively associated with the first portion for eilecting compensation for. any change in the first portion caused by variations of ambient temperature, and a third portion provided with connection means disposed in said opening for directly connecting said third portion to said indicator, one of said connection means being arranged to increase in response to ambient temperature rise, the extent of movement of the indicator produced by said first portion in response to a given rise of temperature of the first portion above the ambient temperature thereby to compensate for the increase in heat loss of said heated portion at higher ambient temperatures.

11. Indicator means comprising an indicator, a plurality oi portions for influencing the movement of said indicator, one of said portions being provided with an electric heating element adapted to be energized'in accordance with the condition to be indicated, means operatively related to said one portion for eiiecting compensation for distortion thereof caused by variations of ambient temperatures, and another portion operatively associated with the other portions being arranged to increase in response to ambient temperatures, the extent of movement of the indicator produced by said one portion in response to a given rise of temperature of said one portion above the am.- bienttemperature thereby to compensate for the increase in heat loss of said heated portion at heigher ambient temperatures. 7 I 12. Indicator means comprising an indicator, heat responsive means engageable with said indicator, saidheat responsive means being provided with an electric heating element adapted to be energized in accordance with the condition to be indicated, means operatively associated with said heat responsive means for effecting compensation for any change in said heat responsive means caused by variations of ambient temperature, and means operatively associated with said heat responsive means and said compensation means actable to supplement the action to be produced by the heat responsive means and arranged to increase in response to temperature rise, the extent of movement of the indicator produced by heat responsive means first referred to in response to a given rise of temperature thereof above the ambient temperature thereby to compensate for the increase in heat loss of said heat responsive means at higher ambient temperatures.

13. An electrical indicating instrument comprising, in combination, bimetallic means which includes an actuating portion and an ambient electrical heating means for the actuating portion, an indicating member actuated by said bimetallic actuating portion, means for applying a mechanical bias to control the movement 01' said indicating member, and bimetallic means constructed and arranged for influencing the operation of said indicating member and being responsive to ambient temperature to vary the bias as said ambient temperature changes.

14. An electrical indicating instrument com- 10. An electrical instrument having bimetallic prising, in combination, a bimetallic actuating member which includes an actuating portion and an ambient temperature compensating portion.

said actuating portion being adapted to be heated,

an indicatinjr member actuable by said bimetallic actuating-portion, means for, applying a bias to said actuating portion, and heat responsive means operatively connected with said actuating memher-and responsive-A0 ambient temperature to the bias, as the ambient temperature changes.

16. Anindicating instrument comprising. in oombinatiom a member adapted to be heated,

an; ambienttemperature compensating member,

an indicating member adapted to be actuated by i the heated member, biasing means actuable on saidindicatinz member, and heat responsive means operatively connected with. one 01' said membersand responsive to. ambient temperature to .vary the bias as the ambient temperature chances.

is. an electrical indicatlns instrument comprisi mdn combinati9n, an actuating member which includes an-actuating portion and an aml2 bient temperature compensatin: portion, said actuating portion-"beingv adapted to be heated. an indicating member actuable by said actuating portion, means (or applying abias to said indicating member, and heat responsive means oneratively connected with said actuatina member and responsive to ambient temperature to vary the bias as the ambient temperature changes.

THEODORE J. SMULSKI.

nnrnnancas crrim The following references are of record in the file of this patent:

UNITED STATES rm'rrm'r'sv 

